This thesis summarizes an examination of the Uapala-Usulutan Ceramic Sphere using Instrumental Neutron Activation Analysis (INAA). Usulutan pottery is found at sites within chiefdoms throughout El Salvador and portions of Honduras during the Late Formative to Early Classic transition (400 BC--AD 250). Usulutan pottery can be divided into two type-varieties: Izalco Usulutan and Bolo Orange. Both type-varieties distinctive for their burnished surface and orange on cream resist decoration. Izalco Usulutan is made with fine textured cream colored clays. Bolo Orange is made with medium to fine texture buff to orange colored clays. Although they are similar in appearance, each type has a different pattern of distribution throughout this region. These patterns of distribution have lead researchers to argue for increased interaction among the chiefdoms. The region marked by this interaction is called the Uapala Ceramic Sphere. While some level of interaction is agreed upon, the specific behaviors that caused these patterns has been debated.;This thesis identifies patterns of Usulutan production and distribution using INAA, which measures the chemical composition of pottery by bombarding samples with neturons through irradiation and then measuring the characteristic energy released by different elements as they release them. The amounts of different elements for each sample are used to group sherds statistically based on compositional similarity. Examination of these groups can identify loci of production and the subsequent movement of pots from these loci to where they are used and deposited.;A total of 229 Usulutan sherds were submitted to INAA and their chemical compositions were compared. Grouping based on compositional similarities revealed that the majority of Usulutan pottery in the Uapala Ceramic Sphere was made locally, although the majority of regions within the sphere either exported or imported Usulutan pottery in varying amounts. These patterns of production and distribution suggest that a combination of exchange and stylistic emulation lead to the Uapala Ceramic Sphere.